Organic semiconductor composition, photovoltaic element, photoelectric conversion device, and method of manufacturing photovoltaic element

Abstract

A photovoltaic element has high photoelectric conversion efficiency as well as excellent processing properties/low environmental load. The organic semiconductor composition includes as an additive a compound in which one or two aromatic rings are substituted with a predetermined number of alkyl groups, alkoxy groups, alkanoyl groups, or thioalkyl groups. There is also a method of manufacturing a photovoltaic element which uses the composition.

The invention claimed is: 
     
       1. An organic semiconductor composition including an electron donating organic semiconductor, an electron accepting organic semiconductor, a solvent and an additive having a boiling point higher than that of the solvent, wherein the additive has a molecular weight of about 198 or below and is one or two or more compounds selected from the group consisting of compounds represented by any one of formulae (1) to (3): 
       
         
           
           
               
               
           
         
         in which in formula (1), A represents any aromatic hydrocarbon group having one ring or a heteroaromatic group having one ring, n is a natural number of 2 or more, R 1 s are the only substituents coupled with the A, R 1 s may be the same or different, and represent a methyl group, an alkoxy group or an alkanoyl group, further, at least one among a plurality of R 1 s is either an alkoxy group or an alkanoyl group, and where a plurality of R 1 s may be combined with one another to form a ring, 
         in which in formula (2), B represents any aromatic hydrocarbon group having two rings or a heteroaromatic group having two rings, n is 1, R 2 s are the only substituents coupled with the B, R 2 s may be the same or different, and represent an alkyl group, an alkoxy group, an alkanoyl group or a thioalkyl group, further, at least one among R 2 s is any one of an alkoxy group, an alkanoyl group and a thioalkyl group, and 
         in which in formula (3), C represents any aromatic hydrocarbon group having one ring or a heteroaromatic group having one ring, n is a natural number of 1 or more, R 3 s are the only substituents coupled with the C, R 3 s may be the same or different, and represent an alkyl group, an alkoxy group, an alkanoyl group or a thioalkyl group, further, at least one among R 3 s is a thioalkyl group, and where a plurality of R 3 s may be combined with one another to form a ring. 
       
     
     
       2. The organic semiconductor composition according to  claim 1 , wherein the additive is a compound in which A in formula (1) is a benzene ring, a compound in which B in formula (2) is a naphthalene ring, or a compound in which C in formula (3) is a benzene ring. 
     
     
       3. The organic semiconductor composition according to  claim 1 , wherein the additive is a compound in which two or more R 1 s are an alkoxy group in formula (1) or a compound in which at least two R 1 s are an alkanoyl group and an alkyl group and form a ring in formula (1). 
     
     
       4. The organic semiconductor composition according to  claim 3 , wherein the additive is a compound in which n is 3 or more and three or more R 1 s are an alkoxy group in formula (1). 
     
     
       5. The organic semiconductor composition according to  claim 4 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       6. The organic semiconductor composition according to  claim 3 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       7. The organic semiconductor composition according to  claim 2 , wherein the additive is a compound in which two or more R 1 s are an alkoxy group in formula (1) or a compound in which at least two R 1 s are an alkanoyl group and an alkyl group and form a ring in formula (1). 
     
     
       8. The organic semiconductor composition according to  claim 2 , wherein the additive is a compound in which n is 1 and R 3  is a thioalkyl group in formula (3). 
     
     
       9. The organic semiconductor composition according to  claim 2 , wherein the additive is a compound in which n is 2 or more and at least one of R 3 s is an alkoxy group in formula (3). 
     
     
       10. The organic semiconductor composition according to  claim 2 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       11. The organic semiconductor composition according to  claim 1 , wherein the additive is a compound in which n is 1 and R 3  is a thioalkyl group in formula (3). 
     
     
       12. The organic semiconductor composition according to  claim 11 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       13. The organic semiconductor composition according to  claim 1 , wherein the additive is a compound in which n is 2 or more and at least one of R 3 s is an alkoxy group in formula (3). 
     
     
       14. The organic semiconductor composition according to  claim 13 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       15. The organic semiconductor composition according to  claim 1 , wherein the electron accepting organic semiconductor is a fullerene compound. 
     
     
       16. The organic semiconductor composition according to  claim 1 , wherein the electron donating organic semiconductor includes a conjugated polymer having a skeleton represented by any one of formulae (4) to (6): 
       
         
           
           
               
               
           
         
         in which in formula (4), R 4 s which may be the same or different represent an alkyl group, an alkoxy group, an optionally substituted heteroaryl group, an optionally substituted aryl group or a thioalkoxy group, and X which may be the same or different represents a sulfur atom, a selenium atom or an oxygen atom, 
         in which in formula (5), R 5 s represent an alkoxycarbonyl group or an alkanoyl group, and Y represents a hydrogen atom or a halogen atom, and 
         in which in formula (6), R 6 s represent an alkyl group, an optionally substituted heteroaryl group or an optionally substituted aryl group. 
       
     
     
       17. The organic semiconductor composition according to  claim 16 , wherein the conjugated polymer is a conjugated polymer represented by formula (7): 
       
         
           
           
               
               
           
         
         in which R 4 s which may be the same or different represent an alkyl group, an alkoxy group, an optionally substituted heteroaryl group, an optionally substituted aryl group or a thioalkoxy group, R 5 s represent an alkoxycarbonyl group or an alkanoyl group, X which may be the same or different represents a sulfur atom, a selenium atom or an oxygen atom, and Y represents a hydrogen atom or a halogen atom. 
       
     
     
       18. A photovoltaic element having an anode, a cathode and a photoelectric conversion layer formed by drying the organic semiconductor composition according to  claim 1  which is formed between the anode and the cathode. 
     
     
       19. A photoelectric conversion device formed with the photovoltaic element according to  claim 18 . 
     
     
       20. A method of manufacturing a photovoltaic element having an anode, a cathode and a photoelectric conversion layer formed between the anode and the cathode, wherein the photoelectric conversion layer is formed by applying/drying the organic semiconductor composition according to  claim 1 .